Project 3: Determination of the minimal MHC-E-restricted SIV epitope targeting required for RhCMV/SIV vaccine-mediated SIV replication arrest efficacy

项目 3：确定 RhCMV/SIV 疫苗介导的 SIV 复制抑制功效所需的最小 MHC-E 限制性 SIV 表位靶向

• 批准号: 10619304
• 负责人: Louis J. Picker
• 金额: $ 43.04万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-22 至 2027-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10619304
• 关键词: Address; Adoptive Immunotherapy; Autologous; Avidity; CD8-Positive T-Lymphocytes; Cells; Characteristics; Cytomegalovirus Vaccines; Cytoprotection; Development; Engineering; Ensure; Epitopes; Genetic Polymorphism; HIV; HIV vaccine; Haplotypes; Immune; Immune response; Immunologics; Infection; Infusion procedures; Intercept; Link; Macaca mulatta; Major Histocompatibility Complex; Mediating; Modeling; Mutation; Peptides; Receptor Cell; Rhesus; SIV; SIV Vaccines; Specific qualifier value; Specificity; Structure; Systemic infection; T cell response; T-Cell Receptor; T-Lymphocyte; Testing; Time; Vaccinated; Vaccination; Vaccinee; Vaccines; Viral; Virus; Virus Diseases; Virus Replication; Work; cross reactivity; design; expression cloning; flexibility; immunogenicity; in vivo; novel; programs; response; vaccine response; vector; vector vaccine

PROJECT 3 - PROJECT SUMMARY Immune responses elicited by strain 68-1 Rhesus Cytomegalovirus vaccine vectors expressing simian immunodeficiency virus (SIV) inserts (RhCMV/SIV) stringently control SIV (via “replication arrest”) in 59% of vaccinees, with subsequent viral clearance over time. The ability of this vaccine to mediate replication arrest has been strongly linked to its ability to elicit SIV-specific CD8+ T cells that recognize viral peptides in the context of functionally non-polymorphic major histocompatibility complex (MHC)-E rather than classical highly polymorphic MHC-Ia. These MHC-E-restricted CD8+ T cell responses intercept primary SIV infection before the massive viral replication and sequence diversification that leads to mutational escape, and thus they may only require effective overall SIV recognition and not necessarily epitope breadth. Preliminary work by our group has found that MHC- E-restricted TCRs and T cell clonotypes are fundamentally different from those of classical MHC-Ia-restricted CD8+ T cell responses. Whereas conventional MHC-Ia-restricted epitope-targeted responses are mediated by independent TCRs, MHC-E-restricted SIV-specific responses (even when directed at numerous SIV epitopes) are largely comprised of only a handful (<10) of independent TCRs that are relatively low avidity and highly cross-reactive – with each TCR recognizing one or more universal epitopes called supertopes (epitopes that are recognized by all 68-1 RhCMV/SIV vaccinated RMs) and a variable number of diverse non-universal epitopes. In this project we seek to define the minimal MHC-E-restricted CD8+ T cell TCR recognition unit capable of mediating SIV replication arrest-type efficacy, asking the questions of whether efficacy requires recognition of one or multiple supertopes, and whether this efficacious recognition requires one or multiple TCR clonotypes (effectively asking whether cross-reactive TCR recognition of multiple SIV epitopes is an intrinsic requirement for effective overall SIV-infected cell recognition and thus for efficacy). Also, given the lack of MHC-E polymorphism, we ask whether development of a universal MHC-E-restricted supertope-targeted HIV vaccine is possible – a vaccine that has similar specificity in all vaccinees and is broadly targeted enough to ensure efficacy- sufficient recognition across global HIV sequence variability. These questions will be answered by addressing the following Specific Aims: S.A.1 - to design and validate SIV inserts for miR-126-restricted (MHC-E-only) 68-1 RhCMV vectors that will (exclusively) elicit SIV MHC-E-restricted SIV-specific CD8+ T cell responses limited to 1, 2, and 10 SIV supertopes; S.A.2 - to compare immunogenicity (including response specificity, TCR clonotypic hierarchies, and TCR cross-reactivity) and replication arrest-type efficacy of single, dual and 10 MHC-E supertope-only vectors; and S.A.3 - to develop ex vivo engineered autologous T cells expressing validated MHC- E-restricted SIV supertope-specific TCRs for in vivo infusion at the time of SIV challenge to determine whether CD8+ T cells expressing protective MHC-E-restricted TCRs can mediate replication arrest efficacy in the absence of RhCMV/SIV vaccination.

项目 3 - 项目摘要 表达猿猴的 68-1 株恒河猴巨细胞病毒疫苗载体引发的免疫反应 免疫缺陷病毒 (SIV) 插入 (RhCMV/SIV) 严格控制 59% 的 SIV（通过“复制停滞”） 随着时间的推移，这种疫苗介导复制停滞的能力已被清除。 与其引发 SIV 特异性 CD8+ T 细胞的能力密切相关，这些 T 细胞在以下情况下识别病毒肽： 功能上非多态性主要组织相容性复合体 (MHC)-E，而不是经典的高度多态性 MHC-Ia。这些 MHC-E 限制性 CD8+ T 细胞反应在大规模病毒感染之前拦截原发性 SIV 感染。 复制和序列多样化导致突变逃逸，因此它们可能只需要有效的 我们小组的初步工作发现 MHC- 整体 SIV 识别，而不一定是表位宽度。 E 限制性 TCR 和 T 细胞克隆型与经典 MHC-Ia 限制性 TCR 和 T 细胞克隆型有根本不同 CD8+ T 细胞反应除外，传统的 MHC-Ia 限制性表位靶向反应是由 独立的 TCR、MHC-E 限制的 SIV 特异性反应（即使针对众多 SIV 表位） 主要由少数（<10）个独立的 TCR 组成，这些 TCR 的亲和力相对较低，但 交叉反应——每个TCR识别一个或多个称为超位的通用表位（表位是 被所有 68-1 RhCMV/SIV 疫苗接种 RM 识别）和数量可变的不同非通用表位。 在这个项目中，我们寻求定义最小的 MHC-E 限制性 CD8+ T 细胞 TCR 识别单元，该单元能够 介导 SIV 复制停滞型功效，提出功效是否需要认可的问题 一个或多个超位，以及这种有效的识别是否需要一种或多个 TCR 克隆型 （有效地询问多个 SIV 表位的交叉反应 TCR 识别是否是一个内在要求 有效的整体 SIV 感染细胞识别，从而提高功效）。 多态性，我们询问开发一种通用的 MHC-E 限制性超位靶向 HIV 疫苗是否可行？ 可能 - 一种在所有疫苗中具有相似特异性并且具有足够广泛针对性以确保功效的疫苗 - 这些问题将通过解决全球艾滋病毒序列变异性得到充分认识。 以下具体目标： S.A.1 - 设计和验证 miR-126 限制性（仅限 MHC-E）68-1 的 SIV 插入片段 RhCMV 载体将（专门）引发 SIV MHC-E 限制的 SIV 特异性 CD8+ T 细胞反应，仅限于 1、2 和 10 SIV 超位；S.A.2 - 比较免疫原性（包括反应特异性、TCR 克隆型） 单、双和 10 MHC-E 的层次结构和 TCR 交叉反应性）和复制停滞型功效 仅超位载体；和 S.A.3 - 开发表达经过验证的 MHC-的离体工程自体 T 细胞 E-限制性 SIV 超位特异性 TCR，用于在 SIV 攻击时进行体内输注，以确定是否 表达保护性 MHC-E 限制性 TCR 的 CD8+ T 细胞可以在缺乏的情况下介导复制停滞功效 RhCMV/SIV 疫苗接种。